This project is concerned with investigating (1) the structural specializations underlying aqueous humor production in the ciliary epithelium; (2) the anatomical devices which control acqueous humor outflow at the sclero-corneal angle; (3) the morphological basis of the blood-acqueous barrier, (4) and its experimental manipulation with paracentesis, systemic administration of hypertonic agents or prostaglandins. Freeze-fracturing and ultrastructural tracers will represent the experimental probes. The precise knowledge of the anatomical mechanisms which regulate the intraocular pressure is necessary for a better understanding of the pathogenesis of glaucomas and for devising new pharmacological methods for their control.